Systems and methods for terminating telephony communications to mobile telephony devices  via a  non-native telephony service provider

ABSTRACT

Systems and methods for terminating telephony communications to a mobile telephony device that is roaming outside of its native service area make use of a mobile roaming termination service. The mobile roaming termination service causes the native mobile telephony service provider that provides service to the mobile telephony device to forward incoming telephony communications directed the native telephone number of the mobile telephony device to a forwarding access number. The mobile roaming termination service receives telephony communications directed to the forwarding access number, and then terminates the telephony communication to the mobile telephony device via any one of multiple different methods. The mobile telephony service provider can be instructed to implement and cancel call forwarding instructions by dialing a special character string on the mobile telephony device.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/492,361, filed Jun. 8, 2012, which is itself a continuation-in-partof U.S. patent application Ser. No. 13/334,849, filed Dec. 22, 2011, theentire contents of both of which are herein incorporated by reference.

FIELD OF THE INVENTION

The invention is related to systems and methods for terminatingtelephony communications to a mobile telephony device. Morespecifically, the invention relates to systems and methods forterminating telephony communications to a mobile telephony device thatis roaming out of its native service area.

BACKGROUND OF THE INVENTION

Mobile telephony devices, such as cellular telephones and mobilecomputing devices with cellular telephony capabilities, are typicallyprovided with service from a cellular service provider. The cellularservice provider typically only provides service to its customers withina defined geographical area, often only within a single country. Thearea served by the provider is considered the “native” service area forcustomers who receive cellular telephone service from the provider.

If a customer who receives cellular telephone service from a first“native” cellular service provider travels to an area outside his nativeservice area, the customer's cellular telephone may be capable ofreceiving cellular service from a second “non-native” cellular serviceprovider that provides coverage in that location. However, because thenon-native cellular service provider is not the customer's regularservice provider, the customer will be charged special “roaming” feesfor receiving incoming communications and for sending outgoingcommunications from that location. Typically, the non-native cellularservice provider charges the user's native cellular service provider forproviding service to the customer's cellular telephone, and the nativecellular service provider then passes those charges along to thecustomer as part of his regular monthly bill. This is true for telephonecalls, text messages, and other forms of telephony communications.

Roaming charges can be exorbitant compared to fees charged for telephonycommunications within the customer's native service area. Internationalroaming charges are particularly expensive, as the rates negotiatedbetween carriers for overseas call termination has been at a premium.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a system level representation of elements that interact witheach other to terminate telephony communications to mobile telephonydevices;

FIG. 2 is a schematic diagram of a controller that may be used topractice one or more embodiments of the present invention;

FIG. 3 is a block diagram illustrating elements of a mobile roamingconnection unit embodying the invention;

FIG. 4 is a diagram illustrating steps of a method embodying theinvention for registering a mobile telephony device with a mobileroaming termination service;

FIG. 5 is a diagram illustrating steps of a method embodying theinventor for implementing call forwarding instructions as part of amethod of terminating telephony communications to mobile telephonydevices;

FIG. 6 is a diagram illustrating steps of a method embodying theinventor for triggering the implementation of call forwardinginstructions as part of a method of terminating telephony communicationsto mobile telephony devices;

FIG. 7 is a diagram illustrating steps of a method embodying theinventor for terminating telephony communications to a mobile telephonydevice;

FIG. 8 is a diagram illustrating steps of another method embodying theinvention for terminating telephony communications to a mobile telephonydevice;

FIG. 9 is a flowchart describing a method in which a character stringthat can be dialed to implement call forwarding is determined andprovided to a telephony device;

FIG. 10 is a flowchart describing another method in which in which acharacter string that can be dialed to implement call forwarding isdetermined and provided to a telephony device; and

FIG. 11 is a flowchart describing a method in which a mobile telephonydevice is caused to dial a character string that causes theimplementation of call forwarding instructions.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

In the following description, references are made to a user's or acustomer's mobile telephony device. This term encompass traditionalcellular telephones, as well as mobile telephony devices that includeadditional functionality, such as the ability to wirelessly communicatedigital data. These terms also encompass mobile computing devices thatinclude communications capabilities provided by either or both of acellular transceiver and a wireless digital data transceiver. Examplesof such devices include the Apple iPhone™, mobile telephony devicesrunning the Android™ operating system, the Blackberry™ and mobiletelephones running the Symbian operating system.

The following description also refers to terminating a telephonycommunication. This phrase refers to completing an incoming telephonycommunication, such as a voice or video telephone call, to a telephonydevice. This phrase also encompasses delivering text messages and otherforms of text-based or video-based messaging to a telephony device. Thisphrase also encompasses other forms of communications that may becarried over a telephony network.

The term “call” or “telephone call” is used in the following descriptionfor ease of reference, clarity and brevity. However, all of the systemsand methods described below which involve handling, routing andterminating calls would also apply to systems and methods of handling,routing and terminating other forms of telephony-based communications.Thus, the terms call and telephone call are intended to include otherforms of telephony-based communications.

The invention provides a method, system and apparatus for terminating atelephony communication to a mobile telephony device that is roaming insuch a way that roaming charges preferably are not incurred. Toaccomplish this, the telephony communication is routed through anInternet Protocol (IP) telephony system which is capable of terminatingthe telephony communication to the mobile telephony device in ways thatdo not incur roaming charges. In some instances, such as where no otheroptions exist, the IP telephony system might deliberately cause thetelephony communication to be terminated to the mobile telephony devicethrough a non-native mobile telephony service provider. While this wouldresult in the user incurring roaming charges, terminating the telephonycommunication in this fashion may be the only way to reach the user.

In some systems and methods embodying the invention, telephonycommunications are effected over a packet-based data network. Signalingthat is conducted in the packet-based data network is preferablyexecuted using Session Initiation Protocol (SIP). SIP is a popularcommunication protocol for initiating, managing and terminating media(e.g., voice, data and video) sessions across packet-based data networksthat typically use the Internet Protocol (IP), of which Voice OverInternet Protocol (VOIP) is an example. The details and functionality ofSIP can be found in the Internet Engineering Task Force (IETF) Requestfor Comments (RFC) Paper No. 3261 entitled, “SIP: Session InitiationProtocol” herein incorporated in its entirety by reference.

SIP establishes and negotiates a session, including the modification ortermination of a session. It uses a location-independent address systemfeature in which called parties can be reached based on a party's name.SIP supports name mapping and redirection, allowing users to initiateand receive communications from any location. Of course, while SIP is apreferred protocol for establishing communications over a data network,other signaling protocols could also be used to perform the invention.

FIG. 1 depicts various elements that may be involved in terminatingtelephony communications to a mobile telephony device. The elements inFIG. 1 include a subscriber mobile telephony device 112. The subscribermobile telephony device 112 may have a native ability to handle voiceover Internet protocol telephony communications sent via a data channel.In other instances, an application running on the subscriber mobiletelephony device 112 may provide the capability of handling voice overInternet protocol telephony communications sent via a data channel.

Mobile telephony service provider A 114 is located in country 1 andprovides telephony service to mobile telephony devices located incountry 1. Mobile telephony service provider A 114 could be, forexample, a cellular telephone network. For purposes of the followingdescription, mobile telephony service provider A 114 is the nativemobile telephony service provider that provides service to thesubscriber mobile telephony device 112.

FIG. 1 also depicts a traditional publically switched telephone network(PSTN) 130. An analog telephone 132 can utilize the PSTN 130 to placeand receive calls. The analog telephone 132 could call the subscribermobile telephony device 112, and the call would be routed through thePSTN 130, then through mobile telephony service provider B 140 to thesubscriber mobile telephony device 112.

FIG. 1 also depicts a cellular telephone 110 that is provided withservice by mobile telephony service provider A 114. The cellulartelephone 110 could call the subscriber mobile telephony device 112through mobile telephony service provider B 140.

FIG. 1 further depicts an IP telephony device 111 that maintains a dataconnection to a packet network, such as the Internet 116. The IPtelephony device 111 is provided with telephony service by an IPtelephony system 124 which is also connected to the Internet 116. If theuser of the IP telephony device 111 wishes to establish a call with thesubscriber mobile telephony device 112, the IP telephony device 111sends a call setup request to the IP telephony system 124 via theInternet 116. The IP telephony system 124 then routes the call throughmobile telephony service provider B 140 to the subscriber mobiletelephony device 112. FIG. 1 also depicts that the IP telephony system124 may use gateways 120A, 120B to communicate with the PSTN 130, mobiletelephony service provider A 114, as well as other telephony serviceproviders.

FIG. 1 further depicts that mobile telephony service provider B 140 islocated in country 2 and provides service to mobile telephony deviceslocated in country 2. Mobile telephony service provider B 140 could alsobe a cellular service provider.

Finally, FIG. 1 illustrates that the subscriber mobile telephony device112 is located in country 2, and it is capable of wirelessly accessingthe Internet 116 via a wireless interface 118. This allows thesubscriber mobile telephony device 112 to send and receive datacommunications over the Internet 116. The wireless interface 118 couldbe a wireless router operating under the WiFi or WiMax standards, or anyother type of wireless interface device that is capable of communicatingwith the subscriber mobile telephony device 112 and the Internet 116. Inother instances, the subscriber mobile telephony device 112 couldestablish a data link to the Internet, or to some other data network, inother ways. For example, the subscriber mobile telephony device 112could communicate through a wireless Local Area Network (LAN), a WideArea Network (WAN) gateway, a hardwired Internet connection and thelike.

Although the subscriber mobile telephony device 112 is capable ofsending and receiving data communications through the wireless interface118, the subscriber mobile telephony device 112 is also capable ofestablishing a data channel through a mobile telephony service provider.The data channel would be separate from a channel used for audiocommunications. Thus, the subscriber mobile telephony device 112 iscapable of sending and receiving data communications via two independentpathways.

As explained above, mobile telephony service provider A 114, located incountry 1, is the native service provider for the subscriber mobiletelephony device 112. When located in country 2, the subscriber mobiletelephony device 112 only has access to mobile telephony serviceprovider B 140 to send and receive telephony communications. Thisresults in the subscriber incurring roaming charges.

As will be described in more detail below, elements of the IP telephonysystem 124 are capable of terminating telephony communications to thesubscriber mobile telephony device 112 via a data connection passingover the Internet 116. In some instances, the IP telephony system 124may also be capable of terminating telephony communications to thesubscriber mobile telephony device 112 via a data connection passingover a data channel provided by mobile telephony service provider B 140.So long as the cost of obtaining that data connection is lower than thecost of receiving a telephone call via mobile telephony service providerB 140 over a mobile voice channel, this may be a preferred way ofterminating the telephony communication to the subscriber mobiletelephony device 112.

FIG. 2 illustrates elements of a computer processor 250 that can be usedas part of the system operated by the IP telephony service provider 124to accomplish various functions. The IP telephony service provider 124could utilize multiple processors 250 located at various locations,along with their operating components and programming, each carrying outa specific or dedicated portion of the functions performed by the IPtelephony service provider 124.

The processor 250 shown in FIG. 2 may be one of any form of a generalpurpose computer processor used in operating an IP based communicationsystem. The processor 250 comprises a central processing unit (CPU) 252,a memory 254, and support circuits 256 for the CPU 252. The processor250 also includes provisions 258/260 for connecting the processor 250 tocustomer equipment via one or more access point, such as the packetnetwork 116, gateways 120A, 120B and a data channel provided by acellular service provider, as well as possibly one or more input/outputdevices (not shown) for accessing the processor and/or performingancillary or administrative functions related thereto. The provisions258/260 are shown as separate bus structures in FIG. 2; however, theymay alternately be a single bus structure without degrading or otherwisechanging the intended operability of the processor 250.

Another form of processor 250 that assists in execution and is otherwisepart of the subject invention is found within one or more of the mobiletelephony devices. Such devices are sufficiently advanced beyond earlygeneration cellular telephones that they contain processors capable ofrunning operating systems developed by device manufactures, as well asthird party applications that are downloaded and installed by users toperforming a myriad of communications and non-communications orientedtasks.

The memory 254 is coupled to the CPU 252. The memory 254, orcomputer-readable medium, may be one or more of readily available memorysuch as random access memory (RAM), read only memory (ROM), floppy disk,hard disk, flash memory or any other form of digital storage, local orremote, and is preferably of non-volatile nature. The support circuits256 are coupled to the CPU 252 for supporting the processor in aconventional manner. These circuits include cache, power supplies, clockcircuits, input/output circuitry and subsystems, and the like.

A software routine 262, when executed by the CPU 252, causes theprocessor 250 to perform processes of the disclosed embodiments, and isgenerally stored in the memory 254. The software routine 262 may also bestored and/or executed by a second CPU (not shown) that is remotelylocated from the hardware being controlled by the CPU 252. Also, thesoftware routines could also be stored remotely from the CPU. Forexample, the software could be resident on servers and memory devicesthat are located remotely from the CPU, but which are accessible to theCPU via a data network connection.

The software routine 262, when executed by the CPU 252, transforms thegeneral purpose computer into a specific purpose computer that performsone or more functions of the IP telephony system 124. Although theprocesses of the disclosed embodiments may be discussed as beingimplemented as a software routine, some of the method steps that aredisclosed therein may be performed in hardware as well as by a processorrunning software. As such, the embodiments may be implemented insoftware as executed upon a computer system, in hardware as anapplication specific integrated circuit or other type of hardwareimplementation, or a combination of software and hardware. The softwareroutine 262 of the disclosed embodiments is capable of being executed onany computer operating system, and is capable of being performed usingany CPU architecture.

The IP telephony system 124 includes a mobile roaming connection unit300, as illustrated in FIG. 3. The mobile roaming connection unit 300includes a registration unit 302, a triggering unit 304, a forwardinginstruction unit 306, a call termination unit 308, and an optional callforwarding code database 310. These elements act together to register amobile telephony device with a mobile roaming termination serviceprovided by the IP telephony system 124. These elements also act todetermine when the service should be activated or deactivated, and toroute telephony communications to registered mobile telephony deviceswhen they are roaming out of their native service area. Wheneverpossible, the mobile roaming connection unit 300 terminates telephonycommunications to a roaming mobile telephony device in a manner thatdoes not result in the user incurring roaming charges.

In some embodiments, any time that the subscriber mobile telephonydevice 112 detects the availability of a data network connection, suchas through the wireless interface 118, the subscriber mobile telephonydevice 112 contacts the mobile roaming connection unit 300 and registerswith same. Once registered, the IP telephony system 124 is capable ofrouting telephony communications to the subscriber mobile telephonydevice 112 via the data network connection. In some embodiments,however, the subscriber mobile telephony device 112 may only attempt toregister with the mobile roaming connection unit if the subscribermobile telephony device determines that it is outside of its nativeservice area and is roaming. In still other embodiments, the subscribermobile telephony device may attempt to register with the mobile roamingconnection unit 300 when it is still within its native service area, butwhen the device is unable to establish a connection to its native mobiletelephony service provider.

Also, in some instances, the subscriber mobile telephony device 112 maydeliberately choose to register itself with the mobile roamingconnection unit 300 when it is within its native service area, and whena cellular channel to mobile telephony service provider A 114 isavailable. This might allow the subscriber mobile telephony device toreceive incoming calls without using up minutes of a calling plan. Inthis instance, the subscriber might configure his subscriber device 112such that whenever the subscriber device 112 detects the availability ofa data network connection, such as a wireless router 118 connected tothe Internet 116, use of the system and methods described above areautomatically initiated.

The registration unit 302 will act to register individual mobiletelephony devices with the mobile roaming termination service. Typicallya subscriber will already have an existing account with the IP telephonysystem 124. However, in some instances, a subscriber could register forthe mobile roaming termination service as its only service from the IPtelephony system 124.

FIG. 4 illustrates steps of a method of registering a mobile telephonydevice with the mobile roaming termination service. As illustrated inFIG. 4, in step S402, the registration unit 302 obtains the nativetelephone number associated with the subscriber mobile telephony device112. This native telephone number may have been assigned by mobiletelephony service provider A 114, or by some other mobile telephonyservice provider. The registration unit 300 then creates a new entry ina registration database for the subscriber mobile telephony device 112that includes the native telephone number.

In step S404, the registration unit 302 obtains an identifier associatedwith the subscriber mobile telephony device 112 from mobile telephonyservice provider A 114. In one embodiment of the invention, theidentifier is an international mobile subscriber identity (IMSI) number.The IMSI number is a unique identifier associated with all GSM and UMTSnetwork mobile telephone users and conforms to the ITU E.212 numberingstandard.

The IMSI number is actually associated with the SIM card present in thesubscriber mobile telephony device 112, and it would be contained in ahome location register that is maintained by mobile telephony serviceprovider A 114. The IMSI number is often required to be used in certaincommunications with a mobile telephony service provider when the mobileservice provider is being asked to take certain actions with respect toa mobile telephony device. In step S406, the registration unit 302stores the IMSI number in the record established for the subscribermobile telephony device 112 in the registration database.

Once the subscriber mobile telephony device 112 has been registered, themobile roaming connection unit 300 will have the information it requiresto cause telephony communications directed to the regular nativetelephone number associated with the subscriber mobile telephony device112 to be re-directed to the IP telephony system 124. This isaccomplished by instructing mobile telephony service provider A 114 toforward calls directed to the native telephone number associated withthe subscriber mobile telephony device 112 to a new access number thatis maintained by the IP telephony system 124. Once call forwardinginstructions have been implemented, all calls placed to the subscribermobile telephony device 112 will instead be received by the IP telephonysystem 124. In some embodiments, this would be accomplished using theRTP and SIP protocols. The IP telephony system 124 can then terminatethe call to the subscriber mobile telephony device 112 in a fashion thatwill not incur roaming charges.

FIG. 5 illustrates steps of a method that would be performed by themobile roaming connection unit 300 to cause the implementation of callforwarding instructions. The method starts in step S502 when thetriggering unit 304 of the mobile roaming connection unit 300 decidesthat forwarding instructions should be issued. The triggering unit 304determines that it is appropriate to implement call forwardinginstructions in response to a variety of different conditions, as willbe described in more detail below.

In step S504, the forwarding instruction unit 306 assigns a forwardingaccess telephone number. The forwarding access telephone number isstored in a registration database maintained by the IP telephony system124 against the native telephone number and IMSI number of thesubscriber mobile telephony device 112. Once the forwarding accessnumber has been assigned, in step S506 the forwarding instruction unit306 issues call forwarding instructions to mobile telephony serviceprovider A 114 to cause mobile telephony service provider A 114 toforward all calls made to the native telephone number of the subscribermobile telephony device 112 to the assigned forwarding access number.Typically, the IMSI number for the subscriber mobile telephony device112 must be used in the communications with mobile telephony serviceprovider A 114 to cause the implementation of the call forwardinginstructions.

The forwarding access telephone number is controlled by the IP telephonysystem 124. Once the call forwarding instructions have been implemented,any calls made to the native telephone number of the subscriber mobiletelephony device 112 are received by the IP telephony system 124. Also,when the IP telephony system 124 receives a call directed to aforwarding access telephone number, the IP telephony system 124 consultsthe registration database to determine which subscriber mobile telephonydevice is associated with that forwarding access telephone number. Inthis fashion, the IP telephony system 124 knows which mobile telephonydevice the caller is trying to reach.

The subscriber mobile telephony device 112 registers itself with themobile roaming connection unit 300 via communications that pass over adata network. Those communications could be sent to the mobile roamingconnection unit 300 over the Internet, via a wireless interface 118.Those communications could also pass over a data channel of a cellularconnection. Regardless, the subscriber mobile telephony device 112 wouldcontact the mobile roaming connection unit 300 and provide information,such as an IP address and a port number, that allows the mobile roamingconnection unit 300 to contact the subscriber mobile telephony device112 and establish a voice over Internet protocol link with thesubscriber mobile telephony device 112. This information would also bestored in the registration database against the other information beingmaintained for the subscriber mobile telephony device 112.

Once call forwarding instructions have been issued, and once thesubscriber mobile telephony device 112 has registered with the mobileroaming connection unit 300, the mobile roaming connection unit 300 canroute incoming calls to the subscriber mobile telephony device 112through a data network. The mobile roaming connection unit 300establishes a VOIP call with the subscriber mobile telephony device 112,and that call is then connected to the inbound call forwarded frommobile telephony service provider A 114.

Because the incoming call is routed through the data network, ratherthan through non-native mobile telephony service provider B 140, noroaming charges will be incurred by the user. The user may have to payto obtain access to the data network. But in many instances, the cost ofaccessing the data network will be lower than the cost of roamingcharges that would otherwise be incurred. For example, if the subscribermobile telephony device 112 uses a wireless access point, such as a WiFirouter, to obtain access to the data network, the charges for suchaccess would likely be far lower than the cost of roaming charges. Evenwhen the subscriber mobile telephony device 112 uses a cellular datachannel to obtain access to a data network, the user would likely incurlower charges for data access than the cost of typical roaming charges.

When the subscriber mobile telephony device 112 registers with themobile roaming connection unit 300, this event may trigger theforwarding instruction unit 306 to issue call forwarding instructions tomobile telephony service provider A 114. However, a variety of othertriggering events might also cause the forwarding instruction unit 306to issue call forwarding instructions. Also, the triggering events thatcause the implementation or cancellation of call forwarding instructionscould be customized for an individual user or for an individualsubscriber mobile telephony device.

FIG. 6 illustrates steps of a method that results in call forwardinginstructions being issued. The method starts in step S602 when thetriggering unit 304 of the mobile roaming connection unit 300 obtainsinformation about the location of the subscriber mobile telephony device112. This could be accomplished by having the triggering unit 304interrogate the subscriber mobile telephony device 112 to obtainlocation information. Alternatively, an application running on thesubscriber mobile telephony device 112 may periodically report theposition of the subscriber mobile telephony device to the triggeringunit 304.

In step S604, the triggering unit 304 compares the location of thesubscriber mobile telephony device 112 to the known native service areaof the device to determine if the subscriber mobile telephony device 112has roamed out of its native service area. If the subscriber mobiletelephony device 112 is roaming, then in step S606, the triggering unitissues forwarding instructions to mobile telephony service provider A114 to have calls placed to the native telephone number of thesubscriber mobile telephony device 112 forwarded to a forwarding accessnumber, as described above. A similar process would be used to cancelcall forwarding instructions when the triggering unit 304 determinesthat the subscriber mobile telephony device has returned to its nativeservice area.

In alternate embodiments, the triggering unit 304 of the mobile roamingconnection unit 300 may monitor the movements of the subscriber mobiletelephony device 112 over an extended period of time. If an analysis ofthe movements of the subscriber mobile telephony device indicate thatthe device travels outside its native service area according to aregular pattern, such as every Monday morning, and/or that the devicetravels back into its native service area according to a regularpattern, such as every Friday evening, then this pattern information maybe used to trigger the implementation and cancellation of callforwarding instructions. Rather than waiting for the actual location ofthe subscriber mobile telephony device to be obtained or reported,forwarding instructions may be automatically implemented and canceledbased on the predicted movements of the device.

In the methods discussed above, the forwarding instruction unit 306 actsto automatically implement and cancel call forwarding instructions basedon the occurrence of an event, or based on a prediction. Likewise, anapplication running on the subscriber mobile telephony device may itselfautomatically cause the implementation and cancellation of callforwarding instructions if the application detects that the device hasmoved out of or back into the subscriber's native calling area. Theapplication may also automatically cause the implementation andcancellation of call forwarding instructions when the applicationdetects that the subscriber mobile telephony device 112 does not have acellular connection to its native mobile telephony service provider A114. Similarly, the application may automatically cause theimplementation and cancellation of call forwarding instructions when theapplication detects that a data network connection is available.

Also, the user might take direct actions to cause the implementation andcancellation of call forwarding instructions. For example, anapplication running on the subscriber mobile telephony device mayprovide a user with the ability to manually cause the implementation andcancellation of call forwarding instructions.

When an application running on the subscriber mobile telephony device112 is causing the implementation of call forwarding instructions, theapplication may be directly communicating with the mobile telephonyservice provider, or the application may communicate with the mobileroaming connection unit 300 to request that it cause the implementationor cancellation of call forwarding instructions. If the application isdirectly interacting with the mobile telephony service provider, theapplication may contact the mobile roaming connection unit 300 via adata network connection to obtain a forwarding access number. Suchcommunications would also inform the mobile roaming connection unit 300that calls received on the forwarding access number should be terminatedto the subscriber mobile telephony device 112. Examples of suchembodiments are discussed in more detail below.

In another embodiment of the invention, all incoming telephonycommunications are forwarded to the IP telephony system 124 at alltimes. This would require that a dedicated forwarding access number beassigned to the subscriber mobile telephony device 112, and callforwarding instructions would always be active. Each time that a call isreceived on the forwarding access number, the mobile roaming connectionunit 300 checks the connection status of the subscriber mobile telephonydevice 112 to determine what type of access the subscriber mobiletelephony device 112 has. The call is then terminated to the subscribermobile telephony device 112 in the most appropriate manner. This couldmean sending the call through a cellular service provider in a normalmanner, or setting up a VOIP telephone link via a data network. If morethan one connection method is possible, preference rules would determinehow the call is connected.

If there is no such access, the incoming telephony communication couldbe sent to voicemail, or to some type of interactive voice responsesystem. Alternatively, the incoming telephony communication could beforwarded to another subscriber device or telephone number.

FIG. 7 illustrates steps of a control method embodying the inventionwhich terminates incoming telephony communications to a subscribermobile telephony device 112 via the most appropriate path. This methodwould be executed by the mobile roaming connection unit 300 of an IPtelephony system 124 after call forwarding instructions have beenimplemented. For purposes of the following explanation, the subscribermobile telephony device 112 is located in country 2 (see FIG. 1), andthe subscriber mobile telephony device is capable of receiving incomingtelephony communications from mobile telephony service provider B 140.

The method begins in step S702 when an incoming telephony communicationis received on a forwarding access number that has been assigned for thesubscriber mobile telephony device 112. In step S704, the calltermination unit 308 of the mobile roaming connection unit 300 checks todetermine if the subscriber mobile telephony device 112 is registeredand reachable via a data network connection. If the subscriber mobiletelephony device 112 is registered, in step S706 the call terminationunit 308 checks to determine the quality of the data connection. If thedata connection is capable of supporting a VOIP call to the subscribermobile telephony device 112, then in step S708 a VOIP call isestablished between the IP telephony system 124 and the subscribermobile telephony device 112 over the data network. The receivedtelephony communication is then terminated to the subscriber mobiletelephony device 112 through the VOIP call.

If the quality of the data network connection to the subscriber mobiletelephony device 112 is not sufficient, then in step S710 a check ismade to determine if the user has authorized calls to be terminated tothe subscriber mobile telephony device 112 through non-native mobiletelephony service provider B 140. This will likely result in roamingcharges. However, the user may choose to accept the roaming charges ifthere is no other way of receiving an incoming telephony communication.In this scenario, the mobile roaming connection unit 300 first checks tosee if it is possible to terminate the call through alternate means. Butif no other means are available, the call is ultimately terminatedthrough the non-native mobile telephony service provider B 140, aftercall forwarding has been canceled.

The result of the decision reached in step S710 could be conditioned onvarious things. For instance, the user may have instructed that allcalls be terminated through non-native mobile telephony service providerB 140 if no other method of terminating the call exists. In otherinstances, the user might specify that calls should only be terminatedthrough a non-native telephony service provider if the call will costless than a threshold amount to complete. In still other instances, theuser might specify that only calls originating from a particular set oftelephone numbers should be completed through a non-native mobiletelephony service provider. This would allow the user to specify thatcertain important people be put through, but that other calls are not.

If the decision in step S710 is that the call should not be terminatedthrough a non-native mobile telephony service provider, then in stepS718 the call is terminated in some other fashion. As discussed above,this could include sending the call to voicemail, playing a recording tothe caller that the called party is unavailable, forwarding the call toan alternate telephone number, or terminating the call in some otherfashion.

If the decision in step S710 is to terminate the call to the subscribermobile telephony device 112 through non-native mobile telephony serviceprovider B 140, in step S712 the forwarding instruction unit 306contacts mobile telephony service provider A 114 and cancels the callforwarding instructions. The call termination unit 308 then sends thecall to the regular native telephone number of the subscriber mobiletelephony device 112 in step S714. This will cause mobile telephonyservice provider A 114 to send the call on to mobile telephony serviceprovider B 140, which ultimately completes the call to the subscribermobile telephony device 112.

Because the call is being routed through the IP telephony system 124,the mobile roaming connection unit 300 is able to monitor the status ofthe call. Once the call is completed, the method proceeds to step S716,where the call forwarding instructions are re-implemented. This ensuresthat further calls directed to the subscriber mobile telephony device112 will be forwarded to the IP telephony system 124.

If the check made in step S704 indicated that the subscriber mobiletelephony device 112 is not registered with the mobile roamingconnection unit 300, then in step S720 a check is made to determine ifit is acceptable to terminate the communication through the non-nativemobile telephony service provider B 140. If the system determines thatthe call should not be terminated through non-native mobile telephonyservice provider B 140, then in step S728 the call would be terminatedin some other fashion.

If the decision in step S720 is to terminate the call to the subscribermobile telephony device 112 through a non-native mobile telephonyservice provider, then in step S722 the forwarding instruction unit 306contacts mobile telephony service provider A 114 and cancels the callforwarding instructions. The call termination unit 308 then sends thecall to the regular native telephone number of the subscriber mobiletelephony device 112 in step S724. This will cause mobile telephonyservice provider A 114 to send the call on to mobile telephony serviceprovider B 140, which ultimately completes the call to the subscribermobile telephony device 112. Once the call is completed, the methodproceeds to step S726, where the call forwarding instructions arere-implemented.

FIG. 8 illustrates steps of another method embodying the invention. Thismethod results in a telephony communication being terminated to asubscriber mobile telephony device 112 that is roaming. The call iscompleted through the non-native mobile telephony service provider B140. However, the call is completed in a fashion that will not result inroaming charges.

When a mobile telephony device is located outside of its native callingarea, the device will communicate with a non-native mobile telephonyservice provider. During an initial communication process, thenon-native mobile telephony service provider will recognize that themobile telephony device is a non-native device. As a result, thenon-native mobile telephony service provider will assign a temporarylocal access telephone number to the device. The temporary number isoften known as a mobile subscriber roaming number (MSRN). The non-nativemobile telephony service provider then communicates with the user'snative mobile telephony service provider and informs the native mobiletelephony service provider of the assigned local access telephonenumber. This can be accomplished using a MAP Update Location Message.

The native mobile telephony service provider stores the temporary localaccess telephone number in a home location register that it maintains.The native mobile telephony service provider can obtain the temporarylocal access telephone number using a MAP Provide Roaming Numbermessage. Whenever a call comes in for the subscriber's mobile telephonydevice, the native mobile telephony service provider forwards the callto the temporary local access telephone number. This will route the callto the non-native mobile telephony service provider, which thencompletes the call to the subscriber's mobile telephony device.

Because the local access number assigned to the subscriber mobiletelephony device 112 by the non-native mobile telephony service providerB 140 is stored in the home location register of the native mobiletelephony service provider A 114, this information may be available tothe IP telephony system 124. For purposes of the following explanation,the subscriber mobile telephony device 112 is roaming in country 2, andmobile telephony service provider B 140 has assigned a local accessnumber to the subscriber mobile telephony device 112. The mobile roamingconnection unit 300 has obtained the local access number from the nativemobile telephony service provider 114. Finally, forwarding instructionsfor the subscriber mobile telephony device have been implemented.

The method begins in step S802, when an incoming telephony communicationdirected to the subscriber mobile telephony device 112 is received bythe IP telephony system 124. In step S804 a check is performed todetermine if the subscriber mobile telephony device 112 is registeredwith the mobile roaming connection unit 300 and available over a dataconnection. If so, then in step S806 the call is completed to thesubscriber mobile telephony device 112 over the data connection.

If the subscriber mobile telephony device is not available over a dataconnection, the method proceeds to step S810, where a check is performedto determine if the mobile roaming connection unit 300 has the localaccess number assigned by the non-native mobile telephony serviceprovider B 140. If the local access number is available, in step S812the mobile roaming connection unit 300 routes the call over a datanetwork to a gateway located in country 2. The gateway in country 2 thencontacts and hands the call off to the non-native mobile telephonyservice provider B 140. The non-native mobile telephony service providerB 140 then completes the call to the subscriber mobile telephony device112.

The IP telephony system 124 already has multiple agreements in placewith mobile telephony service providers in multiple countries. Thoseagreements allow the IP telephony system 124 to route calls over a datanetwork to gateways located in various countries. Those gateways canthen hand calls off to the mobile telephony service providers in thosecountries.

By routing the call over the data network until the call arrives in thedesired country, and by having the non-native mobile telephony serviceprovider then complete the call from a local gateway to the subscribermobile telephony device 112, the call can be completed for aconsiderably lower cost than if the call was handled in a traditionalmanner, and roaming charges were incurred. The user would likely have topay a small charge to terminate the call in this fashion. But the chargewould be less than the cost of the roaming charges.

Returning now to FIG. 8, if the local access number is not available, instep S814 a check is made to determine if it is acceptable to terminatethe communication in the traditional manner through the non-nativemobile telephony service provider B 140. If the system determines thatthe call should not be terminated through the non-native mobiletelephony service provider B 140, then in step S822 the call would beterminated in some other fashion.

If the decision in step S814 is to terminate the call to the subscribermobile telephony device 112 in the traditional manner through thenon-native mobile telephony service provider B 140, then in step S816the forwarding instruction unit 306 contacts mobile telephony serviceprovider A 114 and cancels the call forwarding instructions. The calltermination unit 308 then sends the call to the regular native telephonenumber of the subscriber mobile telephony device 112 in step S818. Thiswill cause mobile telephony service provider A 114 to send the call onto mobile telephony service provider B 140, which ultimately completesthe call to the subscriber mobile telephony device 112. Once the call iscompleted, the method proceeds to step S820, where the call forwardinginstructions are re-implemented.

As an additional feature of the call termination processes presentedabove, an enhanced security option is made available. That is, once acommunication request is passed to the IP telephony system 124, callsignaling and media connections between the IP telephony system 124 andthe subscriber mobile telephony device 112 may be encrypted to provide asecure communication session. The encryption techniques that are usedcould be RSA encryption, as described in PKCS#1 v2.1: RSA CryptographyStandard, RSA Laboratories, dated Jun. 14, 2002, or AES encryption asdescribed in Advanced Encryption Standard (AES), Federal InformationProcessing Standards Publication 197, dated Nov. 26, 2001, or thetechniques described in Secure Socket Layer (now Transport LayerSecurity) Protocol, Version 1.2 as described in IETF RFC 5246, datedAugust 2008, all of which are incorporated herein by reference.

In the methods described above, a call forwarding number is assigned bythe mobile roaming connection unit 300 when call forwarding instructionsare being implemented. This would likely result in different forwardingaccess telephone numbers being used for the same device at differenttimes. However, in other embodiments, the forwarding access telephonenumber could be a dedicated telephone number that is used only for aparticular mobile telephony device.

In the systems and methods described above, a forwarding instructionunit 306 of a mobile roaming connection unit 300 assigns a forwardingaccess telephone number and issues call forwarding instructions tomobile telephony service provider A 114. This causes mobile telephoneservice provider A 114 to forward all calls made to the native telephonenumber of the subscriber mobile telephony device 112 to be forwarded tothe assigned forwarding access number.

In some cases, it may be impossible for the forwarding instruction unit306 of a mobile roaming connection unit 300 to interact directly with amobile telephony service provider to cause the mobile telephony serviceprovider to implement and/or cancel call forwarding instructions. Inthose cases, however, it may be possible for call forwardinginstructions to be implemented and canceled by issuing such instructionsto the mobile telephony service provider from a subscriber's mobiletelephony device. As will be explained below, in some embodiments, asoftware application running on a subscriber's mobile telephony devicecan cause call forwarding instructions to be issued from thesubscriber's mobile telephony device. In other embodiments, thesubscriber may need to take some type of positive action to causeappropriate call forwarding instructions to be issued from thesubscriber's mobile telephony device.

Instructions to implement and cancel call forwarding can be issued to amobile telephony service provider from a subscriber's mobile telephonydevice by dialing predetermined patterns of characters and/or numbers.The call forwarding activation and deactivation codes can vary from onemobile telephony service provider to the next. Thus, it is important toknow which mobile telephony service provider is providing the nativeservice to a subscriber's mobile telephony device to thereby know whichstring of characters must be dialed implement or cancel call forwardinginstructions.

Also, many mobile telephony service providers allow for different typesof call forwarding instructions. Some call forwarding instructions canbe unconditional, whereas other call forwarding instructions can beconditional based on various factors. For example, in many mobiletelephony systems a first call forwarding activation code causes allcalls placed to the native telephone number of a subscriber's mobiletelephony device to be forwarded to a specified forwarding telephonenumber. A second call forwarding activation code causes a call placed tothe native telephone number of a subscriber's mobile telephony device tobe forwarded to a specified forwarding telephone number only if thesubscriber's mobile telephony device is already busy with another call.A third call forwarding activation code causes calls to the nativetelephone number of a subscriber's mobile telephony device to beforwarded to a forwarding telephone number only if the call is notanswered by the subscriber's mobile telephony device within a certainperiod of time after ringing begins.

As with the call forwarding activation codes, different deactivationcodes may be required to deactivate each of these different types ofcall forwarding instructions. The deactivation codes may also vary fromone mobile telephony service provider to the next.

Most subscribers are not aware of the codes that must be dialed on theirmobile telephony device to activate and deactivate call forwarding.Also, in many systems and methods embodying the invention, the callforwarding number that is assigned by the mobile roaming connection unit300 will not be known until it is actually issued by the mobile roamingconnection unit 300. And that may not occur until the subscriber'smobile telephony device registers with the mobile roaming connectionunit 300 via a data connection.

For these reasons, if it is necessary for a subscriber to issue callforwarding instructions to the mobile telephony service provider bydialing a particular string of characters on the subscriber's mobiletelephony device, it is helpful for the mobile roaming connection unit300 to provide the subscriber, or an application on the subscriber'smobile telephony device, with the string of characters that must bedialed. Several different ways of accomplishing this task are explainedbelow.

In many mobile telephony systems, a subscriber can cause unconditionalcall forwarding to be implemented by dialing the string “*21*[forwardingtelephone number]#”. The forwarding telephone number is the telephonenumber to which calls will be forwarded. In the United States, theforwarding telephone number typically includes 10 digits, including thearea code and the assigned telephone number. Once unconditional callforwarding instructions have been implemented, they can be canceled bydialing the string “##21#”.

In many of those same mobile telephony systems, several different typesof conditional call forwarding can be implemented by dialing differentstrings of characters. For example, some telephony systems can beinstructed to forward a call to a forwarding telephone number if thesubscriber's mobile telephony device is busy with another call bydialing the character string “*67*[forwarding telephone number]#”. Thistype of conditional call forwarding can be canceled by dialing thecharacter string “##67#”. Other types of conditional call forwarding canbe implemented and canceled by dialing other character strings.

In the context of this invention, the point of issuing call forwardinginstructions is to cause a subscriber's native mobile telephony serviceprovider to forward an incoming call directed to the native telephonenumber of the subscriber's mobile telephony device to be forwarded to aforwarding access number that has been assigned by a mobile roamingconnection unit 300 of an IP telephony system 124. Once the incomingcall is re-directed to the forwarding access number, the IP telephonysystem 124 completes the call to the subscriber's mobile telephonydevice over a data connection. This requires that the subscriber'smobile telephony device already be registered with the mobile roamingconnection unit 300 via a data connection.

If the forwarding instruction unit 306 of a mobile roaming connectionunit 300 is unable to interact directly with the subscriber's nativemobile telephony service provider to cause the implementation andcancellation of call forwarding instructions, then it would beadvantageous for such call forwarding instructions to be issued bydialing the appropriate character string from the subscriber's mobiletelephony device. Typically, the call forwarding instructions would beissued from the subscriber's mobile telephony device shortly after thesubscriber's mobile telephony device registers with a registration unit302 of the mobile roaming connection unit 300. If a forwarding accesstelephone number is selected upon registration, this is the earliestpoint in time at which the forwarding access telephone number will beknown.

In the following example, the mobile roaming connection unit 300provides the subscriber, or an application on the subscriber's mobiletelephony device, with a character string that must be dialed from thesubscriber's mobile telephony device to implement appropriate callforwarding instructions. In some instances, the subscriber then causesthat character string to be dialed to implement the call forwardinginstruction. In other instances, an application on the subscriber'smobile telephony device causes the character string to be dialed toimplement the call forwarding instructions.

FIG. 9 illustrates steps of a method that would be performed when asubscriber's mobile telephony device registers with a mobile roamingconnection unit 300 to implement mobile roaming procedures by dialing acharacter string from the subscriber's mobile telephony device. Asexplained above, in some embodiments, the subscriber's mobile telephonydevice automatically contacts the mobile roaming connection unit 300whenever it is able to establish a data connection, regardless of howthat connection is established. In other instances, the subscriber takesdirect action to cause his mobile telephony device to register with themobile roaming connection unit 300. In still other instances, the mobileroaming connection unit may initiate contact to the subscriber's mobiletelephony device to cause registration to occur.

The method begins in step S902, where the forwarding instruction unit306 assigns a forwarding access telephone number for the subscriber'smobile telephony device. As explained above, the forwarding accesstelephone number is stored in a registration database maintained by theIP telephony system 124 against the native telephone number and the IMSInumber of the subscriber's mobile telephony device.

Once the forwarding access number is assigned, in step S904 theforwarding instruction unit 306 determines the string of characterswhich must be dialed from the subscriber's mobile telephony device toinstruct the subscriber's native mobile telephony service provider toimplement the desired type of call forwarding.

As explained above, different codes are used by different mobiletelephony service providers to implement and cancel the same type ofcall forwarding instructions. Thus, the forwarding instruction unit 306needs to know what mobile telephony service provider is providing thenative mobile telephony service to the subscriber's telephony device sothat the correct character string can be determined. In someembodiments, a call forwarding code database 310 containing the codes orcharacter strings that are used by various different mobile telephonyservice providers to implement and cancel various different types ofcall forwarding is part of the mobile roaming connection unit 300, orpart of the IP telephony system 124. The call forwarding instructionunit would consult this database to obtain information about how todetermined the correct character string.

As also explained above, many mobile telephony service providers arecapable of implementing multiple different types of call forwarding,each of which is implemented and canceled by different characterstrings. Thus, the forwarding instruction unit 306 also needs todetermine what type of call forwarding the subscriber wishes toimplement, and then determine the character string to use to implementthe desired type of call forwarding within the subscriber's mobiletelephony service provider system.

In some embodiments, the subscriber's preferences about the type of callforwarding will already have been provided to the mobile roamingconnection unit 300 during a registration process. In other instances,the subscriber may be queried about the type of call forwarding he wouldlike to implement each time that the subscriber's mobile telephonydevice registers with the mobile roaming connection unit 300. In someembodiments, if the subscriber has not made a selection regarding thetype of call forwarding instructions he wishes to implement, the mobileroaming connection unit 300 selects a default type of call forwarding,such as unconditional call forwarding.

Once the forwarding instruction unit 306 has determined the characterstring that must be dialed to implement the desired type of callforwarding to the assigned forwarding access number, in step S906, theforwarding instruction unit 306 provides the determined character stringto the subscriber and/or to the subscriber's mobile telephony device inany one of multiple different ways. In some embodiments, the forwardinginstruction unit 306 causes a message to be displayed on thesubscriber's mobile telephony device. The message includes thedetermined character string. The message may also include instructionsfor dialing the determined character string.

In some embodiments, the message could be sent to a software applicationthat is running on the subscriber's mobile telephony device, or that ispresent on a memory card or SIM card of the device, and which is incommunication with the forwarding instruction unit 306 via a dataconnection. The software application then causes the message to bedisplayed on the subscriber's mobile telephony device. In otherembodiments, the forwarding instruction unit 306 could cause a SMS orMMS message to be sent to the subscriber's mobile telephony device via atelephony system connection. In still other embodiments, a pushnotification service could be used to send the desired message to theuser's mobile telephony device.

In the example given above, the character string “*21*[forwardingtelephone number]#” is used to implement unconditional call forwardingto the forwarding telephone number. If the forwarding access numberassigned by the forwarding instruction unit 306 is 703.555.1234, themessage sent to the subscriber's mobile telephony device would includethe string “*21*7035551234#”. The subscriber would dial that characterstring from his mobile telephony device to implement call forwarding tothe telephone number 703.555.1234.

In some instances, it may be relatively easy for the subscriber to copythe provided character string, and to then insert that copied characterstring into the native telephone dialer of the subscriber's mobiletelephony device. In other instances, the subscriber's mobile telephonydevice may have functionality that allows the subscriber to highlight orselect the character string in the displayed message, and to then causethe mobile telephony device to dial the highlighted/selected characterstring. In such instances, it will be relatively easy for the subscriberto cause his mobile telephony device to dial provided character stringto cause the implementation of call forwarding instructions.

One type of call forwarding activation code causes calls to the nativetelephone number of a subscriber's mobile telephony device to beforwarded to a forwarding telephone number if the call is declined bythe subscriber (e.g., by pressing decline when the call is firstreceived by the mobile telephony device and the mobile telephony devicebegins ringing). This fourth type of call forwarding activation code maybe advantageous in allowing the subscriber to choose how an incomingcall is ultimately connected to his mobile telephony device.

For example, in some instances, a subscriber may find that heexperiences superior call quality using a cellular telephony channel, asopposed to a data channel. Thus, depending upon the nature of the phonecall, the user may prefer that an incoming call be connected to hismobile telephony device via a cellular telephony channel, which wouldincur roaming charges, as opposed to receiving the call through a datanetwork via an assigned call forwarding number.

If conditional call forwarding instruction are issued to thesubscriber's native mobile telephony service provider that only resultin a call being forward to a forwarding access number if the subscriberdeclines an incoming call, the subscriber will be able to choose how thecall is connected to his mobile telephony device. If the subscribersimply answers an incoming telephone call when his mobile telephonydevice begins to ring, the call will be connected to the subscriber'smobile telephony device via a roaming cellular connection, which mightprovide higher call quality. On the other hand, if the subscriberdeclines the call, the subscriber's native mobile telephony serviceprovider will forward the call to a forwarding access number assigned bythe mobile roaming connection unit, and the call will be routed to thesubscriber's mobile telephony device via a data connection, as describedabove.

FIG. 10 illustrates a method in which the forwarding instruction unit306 sends a character string that is to be used to implement callforwarding to a subscriber's mobile telephony device in a way that makesit easy for the subscriber to dial the provided string. In step S1002,the forwarding instruction unit 306 assigns a forwarding accesstelephone number. Once the forwarding access telephone number isassigned, the forwarding instruction unit 306 determines the characterstring that must be dialed from the subscriber's mobile telephony deviceto implement a desired type of call forwarding to the assignedforwarding access number in step S1004. In step S1006, the forwardinginstruction unit 306 provides the character string to the subscriber'smobile telephony device in a manner that allows the character string tobe recorded as part of a contact in a contact list that is present onthe subscriber's mobile telephony device.

In some embodiments, the forwarding instruction unit 306 causes atelephone call or a SMS/MMS message to be sent to the subscriber'smobile telephony device. The call or SMS/MMS message includes user IDinformation. The user ID information includes the determined characterstring as the “telephone number” of the calling party. The name providedin the caller ID information could provide an indication of the functionof the character string. For example, the name in the caller IDinformation could read “Implement Call Forwarding for Mobile Roaming.”

When the call or message is received by the subscriber's mobiletelephony device, the caller ID information that includes the determinedcharacter string, and possibly a label indicating the purpose of thecharacter string, will be recorded in the incoming call log of thesubscriber's mobile telephony device. Many mobile telephony devicesprovide the subscriber with the ability to use the caller ID informationthat has been captured for an incoming telephony communication topopulate a new contact entry in a contact list that is stored on thesubscriber's mobile telephony device. Thus, the subscriber is able tostore a new contact in his contact list that includes the characterstring that must be dialed to implement call forwarding as the“telephone number” of the new contact. Likewise, the name in the callerID information, which can include a label indicating the purpose of thecharacter string, will appear as the name of the new contact.

Once the new contact has been stored on the subscriber's mobiletelephony device, the subscriber can request that a call be placed tothat contact. This would cause the subscriber's mobile telephony deviceto dial the character string which implements the required type of callforwarding.

The forwarding instruction unit 306 could also place multiple calls orsend multiple messages to the subscriber's mobile telephony device todeliver character strings and corresponding labels for multipledifferent types of call forwarding instructions. For example, theforwarding instruction unit 306 could place a first call to thesubscriber's mobile telephony device with a character string used toimplement unconditional call forwarding to an assigned forwarding accessnumber. The subscriber would cause this first character string to bestored as part of a first new contact under the name “ImplementUnconditional Call Forwarding.” The forwarding instruction unit 306could then place a second call to the subscriber's mobile telephonydevice with the character string used to implement a type of conditionalcall forwarding to the assigned forwarding access number which occursonly if the subscriber's mobile telephony device is busy, or if thesubscriber declines an incoming call. The subscriber would cause thissecond character string to be stored as part of a second new contactunder the name “Implement Conditional Call Forwarding.” The subscribercould then choose which type of call forwarding is to be implemented byplacing a call to the contact which causes the desired type of callforwarding instructions to be implemented.

In the same way that a character string can be stored as a contact thatis used to implement a desired form of call forwarding, a contact with acharacter string that is dialed to cancel call forwarding could also bestored on the subscriber's mobile telephony device under a name such as“Cancel Call Forwarding.” As noted above, in some mobile telephonyservice provider systems, the character string “##21#” can be dialedfrom a mobile telephony device to cancel unconditional call forwarding.Thus, the forwarding instruction unit 306 could send a call or a messageto the subscriber's mobile telephony device that includes caller IDinformation including the character string “##21#” as the sourcetelephone number, and “Cancel Unconditional Call Forwarding” as thename. The subscriber could then create a new contact with thisinformation. And once created, the subscriber could simply request thata call be placed to the contact with the name “Cancel Unconditional CallForwarding” to cause his mobile telephony device to dial the characterstring which causes the cancellation of unconditional call forwarding.

Because the character string used to cancel call forwarding instructionsdoes not typically include a telephone number, it would be possible fora subscriber to store contacts having the character strings forcancellation of each type of call forwarding instructions. Thosecontacts could then be re-used multiple times whenever a subscriberwishes to cancel a particular type of call forwarding.

On the other hand, if a new call forwarding access number is assigned toa subscriber's mobile telephony device each time the mobile telephonydevice registers with the mobile roaming connection unit 300, it wouldbe necessary for the subscriber to store a new contact in his contactlist (with a character string that includes the newly assignedforwarding access telephone number) each time that the mobile telephonydevice re-registers with the mobile roaming connection unit 300. It isunlikely that a previously stored contact could be re-used to implementmobile roaming operations at a later point in time, because at thatlater point in time a new forwarding access number will have beenassigned to the subscriber's mobile telephony device. And that newforwarding access telephone number will not be reflected in thetelephone number information that is present in the first contact thatwas stored in the subscriber's contact list.

However, if the mobile roaming connection unit 300 assigns a staticforwarding access number to the subscriber's mobile telephony device foran enduring period of time, the subscriber could store a contact in hiscontact list having a telephone number that is the character stringincluding the static forwarding access number. That contact could bere-used multiple times by the subscriber to implement call forwardinginstructions. Software on the subscriber's mobile telephony device couldautomatically create the contact.

For example, assume that a subscriber travels to another country onbusiness, that country being outside the subscriber's native telephonyservice area, and the subscriber intends to remain in the country for aweek. Under those circumstances, the mobile roaming connection unit 300could assign a forwarding access number to the subscriber's mobiletelephony device that will remain tied to the mobile telephony devicefor the entire week. A first contact including the character string forimplementing call forwarding to the assigned forwarding access numbercould then be stored on the subscriber's mobile telephony device. Asecond contact having the character string used to cancel those callforwarding instructions could also be stored on the subscriber's mobiletelephony device. This would allow the subscriber to selectivelyimplement and cancel call forwarding instructions (and thus, mobileroaming operations) by requesting that calls be placed to the first andsecond stored contacts over the duration of his visit to the foreigncountry.

In the systems and methods described above in connection with FIGS. 9and 10, it was assumed that the mobile roaming connection unit 300 wasunable to interact directly with the mobile telephony service providerthat provides telephony service to a subscriber's mobile telephonydevice to selectively implement and cancel call forwarding instructions.For this reason, in the systems and methods discussed above, thecharacter strings required to implement and cancel call forwardinginstructions are provided to the subscriber, via his mobile telephonydevice. The subscriber directly interacts with his device to selectivelyimplement and cancel call forwarding instructions (and thus mobileroaming operations).

Unfortunately requiring the subscriber to implement and cancel callforwarding instructions is not ideal. Some subscriber will likely viewthis as inconvenient and/or too difficult. Also, there is a danger thata subscriber may implement call forwarding instructions (to implementmobile roaming operations), and then forget to cancel the callforwarding instructions once mobile roaming is not longer needed ordesired.

In other situations, the subscriber may not be aware when his mobiletelephony device can no longer maintain a data connection with themobile roaming connection unit 300. If that occurs, the subscriber maynot even be aware that he should cancel call forwarding instructions sothat incoming calls can be received (albeit in a more expensive fashion)via a normal cellular connection.

For all these reasons, in some situations it is desirable for theimplementation and cancellation of call forwarding instructions to beperformed automatically at the appropriate times. However, as alsoexplained above, in some situations the only way to implement and cancelcall forwarding instructions is have the subscriber's mobile telephonydevice dial a particular character string.

FIG. 11 illustrates steps of a method where call forwarding instructionscan be automatically implemented and canceled, without requiring theuser to take any active steps, even through a character string must bedialed by the subscriber's mobile telephony device to implement andcancel the call forwarding instructions. In step S1102, the forwardinginstruction unit 306 assigns a forwarding access telephone number. Oncethe forwarding access telephone number is assigned, in step S1104 theforwarding instruction unit 306 determines the character string thatmust be dialed from the subscriber's mobile telephony device toimplement the desired type of call forwarding to the assigned forwardingaccess number.

In step S1106, the forwarding instruction unit 306 causes thesubscriber's mobile telephony device to dial the determined characterstring. In some embodiments, it may be possible for the forwardinginstruction unit 306 to interact directly with the subscriber's mobiletelephony device via a data connection to cause the native dialer of thesubscriber's mobile telephony device to dial the determined characterstring. In other embodiments, the forwarding instruction unit 306 mayprovide the character string to an application that is present on thesubscriber's mobile telephony device, along with a direction to causethe character string to be dialed. The application would then cause thenative dialer on the subscriber's mobile telephony device to dial thecharacter string.

In a similar fashion, the forwarding instruction unit 306 can determinea character string that will cause call forwarding to be canceled, andthe forwarding instruction unit 306 can cause the native dialer on thesubscriber's mobile telephony device to dial the character string thatcancels call forwarding. This could occur because the forwardinginstruction unit 306 is able to interact directly with the native dialervia a data connection, or because the forwarding instruction unit 306instructs an application on the subscriber's mobile telephony device tocause the dialing of the cancellation string.

In alternate embodiments, the forwarding instruction unit 306 maycontact and/or control the native dialer of the user's mobile telephonydevice through a connection via a cellular data channel, as opposed someother type of data connection. The forwarding instruction unit 306 mightalso provide instructions to an application running on the subscriber'smobile telephony device via the cellular data connection.

In still other embodiments, the forwarding instruction unit 306 mayprovide instructions to an application running on the subscriber'smobile telephony device via a push notification. For example, theforwarding instruction unit 306 may cause a push notification to be sentto the subscriber's mobile telephony device that includes the message“Would you like to implement mobile roaming operations?” If the userresponds affirmatively, a message would be delivered to an applicationon the subscriber's mobile telephony device that causes the applicationto access and control the native dialer on the subscriber's mobiletelephony device so that a character string is dialed to implement callforwarding to an assigned forwarding access number. In some instances,the push notification will also cause the application to load and run.Similar push notifications could be used in a similar fashion to causethe cancellation of call forwarding instructions, and thus thetermination of mobile roaming operations.

While foregoing is directed to embodiments of the present invention,other and further embodiments of the invention may be devised withoutdeparting from the basic scope thereof, and the scope thereof.

1. A method for canceling call forwarding instructions that havepreviously been implemented by a native telephony service provider thatprovides a telephony device with its native telephony service, thetelephony device having a native telephone number, where the callforwarding instructions resulted in incoming telephony communicationsdirected to the native telephone number being directed to a forwardingaccess number, the method comprising: determining whether previouslyimplemented call forwarding instructions for the telephony device shouldbe canceled, wherein the determining step is performed by at least oneprocessor of a computing device; and causing, when the result of thedetermining step is positive, the native telephony service provider tocancel the previously implemented call forwarding instructions such thatincoming telephony communications directed to the native telephonenumber are no longer directed to the forwarding access number and areinstead routed to the native telephone number.
 2. The method of claim 1,wherein the causing step comprises communicating with the nativetelephony service provider to cause the native telephony serviceprovider to cancel the call forwarding instructions.
 3. The method ofclaim 1, further comprising: determining a character string that can bedialed from the telephony device to cause the native telephony serviceprovider to cancel the call forwarding instructions; and providing thedetermined character string to the telephony device.
 4. The method ofclaim 3, further comprising causing the telephony device to dial thedetermined character string.
 5. The method of claim 3, wherein theproviding step comprises providing the determined character string to anapplication running on the telephony device, and further comprisinginstructing the application to cause the telephony device to dial thedetermined character string.
 6. The method of claim 3, wherein theproviding step comprises causing a message to be displayed or played onthe telephony device, the message including the determined characterstring.
 7. The method of claim 3, wherein the providing step comprisessending a telephony communication to the telephony device, wherein thetelephony communication includes caller ID information that includes thedetermined character string.
 8. The method of claim 7, wherein thedetermined character string is provided as the calling telephone numberin the caller ID information of the telephony communication.
 9. Themethod of claim 1, wherein the determining step comprises checking astatus of a data connection between a non-native telephony serviceprovider and the telephony device, and wherein the determination aboutwhether the call forwarding instructions should be canceled is based onthe status of the data connection.
 10. The method of claim 9, wherein ifno data connection exists between the non-native telephony serviceprovider and the telephony device, it is determined that the callforwarding instructions should be canceled.
 11. The method of claim 9,wherein if a quality of a data connection between the non-nativetelephony service provider and the telephony device is below a thresholdvalue, it is determined that the call forwarding instructions should becanceled.
 12. The method of claim 1, wherein the determining stepcomprises: determining a location of the telephony device; anddetermining if the telephony device is within its native service area,and wherein it is determined that the call forwarding instructionsshould be canceled if the telephony is determined to be located withinits native service area.
 13. The method of claim 12, wherein determininga location of the telephony device comprises receiving locationinformation from the telephony device.
 14. The method of claim 1,wherein the determining step comprises receiving a communicationindicating that call forwarding instructions should be canceled.
 15. Themethod of claim 14, wherein the communication is received from thetelephony device.
 16. The method of claim 14, wherein the communicationis received from an application running on the telephony device.
 17. Asystem for canceling call forwarding instructions that have previouslybeen implemented by a native telephony service provider that provides atelephony device with its native telephony service, the telephony devicehaving a native telephone number, where the call forwarding instructionsresulted in incoming telephony communications directed to the nativetelephone number being directed to a forwarding access number, themethod comprising: means for determining whether previously implementedcall forwarding instructions for the telephony device should becanceled, wherein the determining step is performed by at least oneprocessor of a computing device; and means for causing, when the resultof the determining step is positive, the native telephony serviceprovider to cancel the previously implemented call forwardinginstructions such that incoming telephony communications directed to thenative telephone number are no longer directed to the forwarding accessnumber and are instead routed to the native telephone number.
 18. Asystem for canceling call forwarding instructions that have previouslybeen implemented by a native telephony service provider that provides atelephony device with its native telephony service, the telephony devicehaving a native telephone number, where the call forwarding instructionsresulted in incoming telephony communications directed to the nativetelephone number being directed to a forwarding access number, themethod comprising: a triggering unit that determines whether previouslyimplemented call forwarding instructions for the telephony device shouldbe canceled; and a forwarding instruction unit that causes the nativetelephony service provider to cancel the previously implemented callforwarding instructions such that incoming telephony communicationsdirected to the native telephone number are no longer directed to theforwarding access number and are instead routed to the native telephonenumber.
 19. The system of claim 18, wherein the forwarding instructionunit determines a character string that can be dialed from the telephonydevice to cause the native telephony service provider to cancel the callforwarding instructions, and wherein the forwarding instruction unitprovides the determined character string to the telephony device. 20.The system of claim 19, wherein the forwarding instruction unit alsocauses the telephony device to dial the determined character string. 21.The system of claim 19, wherein the forwarding instruction unit causes amessage to be displayed or played on the telephony device, the messageincluding the determined character string.
 22. The system of claim 18,wherein the triggering unit checks a status of a data connection betweena non-native telephony service provider and the telephony device, anddetermines whether the call forwarding instructions should be canceledbased on the status of the data connection.
 23. The system of claim 22,wherein if the triggering unit determines that a quality of a dataconnection between the non-native telephony service provider and thetelephony device is below a threshold value, the triggering unitdetermines that the call forwarding instructions should be canceled. 24.The system of claim 18, wherein the triggering unit determines that thecall forwarding instructions should be canceled if the telephony isdetermined to be located within its native service area.
 25. The systemof claim 18, wherein the triggering unit determines that the callforwarding instructions should be canceled in response to receipt of acommunication sent from the telephony device.
 26. The method of claim 1,further comprising: determining whether call forwarding instructionsshould be re-implemented; and causing, when the determining stepdetermines that the call forwarding instructions should bere-implemented, the native telephony service provider to implement newcall forwarding instructions.
 27. The method of claim 1, wherein theforwarding access number is used to route communications directed to thenative telephone number to a non-native telephony service provider.